Ecomorphological Traits Determine Assemblage Pattern of Small Freshwater Fish in Smaller Lentic Aquatic Bodies

The present study investigated ecomorphological patterns of fish assemblage from freshwater ponds on two functional categories, i.e., foraging behavior and habitat preference. Nine ecomorphological indices were derived from eight morphometric variables and examined on 566 adult individuals belonging to 9 species, 7 families and 4 orders. Samples were collected during April 2016 to September 2017 from freshwater ponds in Birbhum, West Bengal. Mantel test was performed to investigate correlation between morphological, taxonomic, trophic and habitat guild matrices. The partial Mantel test was done to investigate the direct correlation between trophic and habitat guilds with morphology discounting the effect of taxonomic relatedness on species assemblage. The interspecific ecomorphological diversification pattern was analysed by HCPC method. At least three ecomorphological assemblages among these fish species with two significant principal axes of variations were observed. Ecomorphological attributes associated with mouth aspect ratio, compression index and relative body height were on PC1 axis, and relative length and height of head, relative area of eye were on PC 2 axis. Mantel and partial Mantel test showed significant correlation between morphology and trophic guild structure. Outcomes show that morphology is a good predictor of trophic structure of fish assemblage in studying convergent assemblage pattern irrespective of taxonomy.

Ecomorphological relationships of fish assemblages in a trans-Andean drainage, Upper Magdalena River Basin, Colombia

ABSTRACT Ecomorphological patterns of the fish community were evaluated in the trans-Andean Alvarado River drainage, Colombia. A total of 29 species using 25 ecomorphological indices were analyzed to test how well the ecomorphological patterns are related to the fish assemblage. Although a significant correlation was found (Mantel test) between morphological attributes and trophic guilds, habitat use and distribution across the altitudinal gradient, only the last two were significantly independent of the phylogenetic relationships (partial Mantel test). Regarding the ecomorphological space, two main trends were defined. First, benthic periphytivores and invertivores were characterized by having dorsal or dorsolateral eyes, labial appendages, depressed bodies and well-developed pectoral, ventral and caudal fins, which provide them the ability to stabilize over the substrate and make rapid movements. Second, nektonic detritivore-invertivores and insectivores were found to have laterally compressed bodies, lateral eyes and larger eyes and anal fins. These species use vision during predation, are good continuous swimmers and possess higher maneuverability and stability. These results show that the fish assemblages in the Alvarado River drainage are structured ecomorphologically mainly by habitat and the altitudinal gradient. Therefore, this is evidence of the importance of habitat structure to maintain the functionality of the ecosystem.

Size and shape in Melipona quadrifasciata anthidioides Lepeletier, 1836 (Hymenoptera; Meliponini)

This study aimed to identify differences in wing shape among populations of Melipona quadrifasciata anthidioides obtained in 23 locations in the semi-arid region of Bahia state (Brazil). Analysis of the Procrustes distances among mean wing shapes indicated that population structure did not determine shape variation. Instead, populations were structured geographically according to wing size. The Partial Mantel Test between morphometric (shape and size) distance matrices and altitude, taking geographic distances into account, was used for a more detailed understanding of size and shape determinants. A partial Mantel test between morphometris (shape and size) variation and altitude, taking geographic distances into account, revealed that size (but not shape) is largely influenced by altitude (r = 0.54 p < 0.01). These results indicate greater evolutionary constraints for the shape variation, which must be directly associated with aerodynamic issues in this structure. The size, however, indicates that the bees tend to have larger wings in populations located at higher altitudes.

Genetic and phenotypic variation in Lotus japonicus (Regel) K. Larsen, a model legume species

Mimura, M. 2013. Genetic and phenotypic variation in Lotus japonicus (Regel) K. Larsen, a model legume species. Can. J. Plant Sci. 93: 435–444. Lotus japonicus is a model legume species with more than 90% of its gene space determined; however, its ecological and evolutionary background is little known. The genetic and phenotypic variation of this model species was investigated within the Japanese Archipelago, where it exists in various climates and has experienced repeated vegetative shifts in conjunction with historical climate changes, using nuclear microsatellite loci and common garden experiments. The partial Mantel test was performed to detect the influence of phylogeographic effects on phenotypic variation among accessions along environmental gradients. Western Japan showed more complex genetic population structures than northern Japan, which may reflect past population dynamics. The total biomass demonstrated clinal variation with a climatic variable (ClimatePC). The trend was significant in a partial Mantel test when controlling for genetic distance, which is independent of the environmental distance. This suggests adaptive divergence within the Japanese Archipelago. With highly accessible genome information, L. japonicus appears to be a promising species for future ecological and evolutionary studies.

Similarities among ectoparasite fauna of sigmodontine rodents: phylogenetic and geographical influences

SUMMARYPhylogenetic and geographical overlaps in host distributions influence the compositional similarity of ectoparasite fauna in a host–parasite system. In these systems, hosts that are more closely related (phylogenetically) are expected to share more parasitic species than more distantly related hosts. Similarly, hosts sharing a larger geographical distribution overlap are expected to have similar ectoparasites. This study investigated the influence of phylogeny (divergence time) and geographical overlap of some neotropical sigmodontine rodent species on the similarities among their ectoparasite fauna (Mesostigmata and Siphonaptera), using a partial Mantel test. Divergence time was the only significant factor that influenced the similarity among the ectoparasites, when mites and fleas were analysed together. Host species that had diverged more recently displayed ectoparasite fauna that were similar. The similarities of the flea species showed similar results in both separate and joint analyses, but neither phylogenetic nor geographical overlap influenced the similarity in mite species. Fleas were shown to be more host-specific than were mesostigmate mites, probably because of the increased influence of host phylogeny.

Biogeographic patterns of fish species richness in Ontario lakes in relation to historical and environmental factors

Fish species richness in Ontario lakes was summarized for 80 equal-area quadrats and ranged from 59 species per quadrat in southwestern Ontario to 17 species per quadrat in northern Ontario. Correlograms based on Moran's I coefficient indicated the spatial structure of lake species richness was anisotropic and exhibited a strong south–north gradient of decreasing richness. Relationships among Euclidean distance matrices based on richness, postglacial dispersal, climate, elevation, lake chemistry, and lake morphometry were identified with the aid of the Mantel test and principal coordinates analysis. The presence of spatial autocorrelation may bias matrix correlations; therefore, spatial autocorrelation was removed using the partial Mantel test. The results of the partial Mantel test indicated regional lake species richness was significantly correlated with postglacial dispersal and climate. In particular, the results of principal coordinates analysis identified length of time since deglaciation, length of time covered by glacial lakes, distance from dispersal corridor, and mean annual air temperature as the dominant variables in these data sets.